GOP Presidential front runner Donald Trump says New York City Mayor Bill de Blasio “made a terrible mistake” when he shut down one of the city’s intelligence units that engaged in surveillance of mosques suspected of being centers of terrorism.

“We had a very strong [intelligence] unit. We did a lot of surveillance of mosques in our city, in New York City, and from what I understand we’re not doing that any more [under Mayor de Blasio]. I think that’s a terrible mistake,” Trump, a New York City resident who began his real estate empire in Manhattan, told Breitbart Executive Chairman Stephen K. Bannon on Sirius XM’s Breitbart News Daily radio program.

Bannon asked Trump his view on the”firestorm of criticism from the left and the Republican establishment” about his statement he would “strongly consider” shutting down some mosques if necessary “particularly given what’s happened in Paris today with the prime minister talking about potential chemical and biological warfare.”

“I think that could very well happen. It’s getting worse and worse. There’s hatred, and there’s hatred like nobody’s ever seen, and it’s obviously emanating from and coming out of, among other places, the mosques. There’s tremendous, something going on in those mosques that is not lovely. That I can tell you and that you know,” Trump told Bannon.

Trump also doubled down on his position that the United States should shut down the current influx of Syrian refugees coming into the United States.

“Nobody, nobody, under the [Syrian] migration, nobody comes into this country. Because I have no doubt that ISIS is coming in [to the United States] under the guise [of Syrian refugees],” Trump told Bannon.

Though the Obama administration has publicly said it plans on bringing 10,000 Syrian refugees into the United States over the next 12 months, Trump told Bannon “[y]ou know he’s not going to stop. If he got 60 or 65 [thousand], you know he’s not going to stop.”

“Obama wants to bring not the 10,000, not the 15,000, not even the 65,000 that they talked about in the Democrat debate. Obama wants to bring, I hear, between 200,000 and 250,000 into the country. That’s what I hear the number is,” Trump concluded.